mirror of https://github.com/docker/docs.git
78 lines
2.1 KiB
Perl
Executable File
78 lines
2.1 KiB
Perl
Executable File
#!/usr/bin/perl
|
|
#
|
|
# A simple helper script to help people build seccomp profiles for
|
|
# Docker/LXC. The goal is mostly to reduce the attack surface to the
|
|
# kernel, by restricting access to rarely used, recently added or not used
|
|
# syscalls.
|
|
#
|
|
# This script processes one or more files which contain the list of system
|
|
# calls to be allowed. See mkseccomp.sample for more information how you
|
|
# can configure the list of syscalls. When run, this script produces output
|
|
# which, when stored in a file, can be passed to docker as follows:
|
|
#
|
|
# docker run --lxc-conf="lxc.seccomp=$file" <rest of arguments>
|
|
#
|
|
# The included sample file shows how to cut about a quarter of all syscalls,
|
|
# which affecting most applications.
|
|
#
|
|
# For specific situations it is possible to reduce the list further. By
|
|
# reducing the list to just those syscalls required by a certain application
|
|
# you can make it difficult for unknown/unexpected code to run.
|
|
#
|
|
# Run this script as follows:
|
|
#
|
|
# ./mkseccomp.pl < mkseccomp.sample >syscalls.list
|
|
# or
|
|
# ./mkseccomp.pl mkseccomp.sample >syscalls.list
|
|
#
|
|
# Multiple files can be specified, in which case the lists of syscalls are
|
|
# combined.
|
|
#
|
|
# By Martijn van Oosterhout <kleptog@svana.org> Nov 2013
|
|
|
|
# How it works:
|
|
#
|
|
# This program basically spawns two processes to form a chain like:
|
|
#
|
|
# <process data section to prefix __NR_> | cpp | <add header and filter unknown syscalls>
|
|
|
|
use strict;
|
|
use warnings;
|
|
|
|
if( -t ) {
|
|
print STDERR "Helper script to make seccomp filters for Docker/LXC.\n";
|
|
print STDERR "Usage: mkseccomp.pl < [files...]\n";
|
|
exit 1;
|
|
}
|
|
|
|
my $pid = open(my $in, "-|") // die "Couldn't fork1 ($!)\n";
|
|
|
|
if($pid == 0) { # Child
|
|
$pid = open(my $out, "|-") // die "Couldn't fork2 ($!)\n";
|
|
|
|
if($pid == 0) { # Child, which execs cpp
|
|
exec "cpp" or die "Couldn't exec cpp ($!)\n";
|
|
exit 1;
|
|
}
|
|
|
|
# Process the DATA section and output to cpp
|
|
print $out "#include <sys/syscall.h>\n";
|
|
while(<>) {
|
|
if(/^\w/) {
|
|
print $out "__NR_$_";
|
|
}
|
|
}
|
|
close $out;
|
|
exit 0;
|
|
|
|
}
|
|
|
|
# Print header and then process output from cpp.
|
|
print "1\n";
|
|
print "whitelist\n";
|
|
|
|
while(<$in>) {
|
|
print if( /^[0-9]/ );
|
|
}
|
|
|